1. Field of the Invention
This invention relates to laminated devices and methods of making same.
2. Background Art
Nominally, microchannels can be defined as channels whose dimensions are less than 1 mm and greater than 1 xcexcm. Above 1 mm, the flow exhibits behavior that is the same as most macroscopic flows. Below 1 xcexcm, the flow is better characterized as nanoscopic. Currently, most microchannels fall into the range of 30 to 300 xcexcm. Microchannels can be fabricated in many materialsxe2x80x94glass, polymers, silicon and metals using various processes including surface micromachining, bulk micromachining, molding, embossing and conventional machining with microcutters.
One type of mechanical micropump is the positive-displacement pump. These are mechanical pumps with a membrane or diaphragm actuated in a reciprocating mode and with unidirectional inlet and outlet valves. They work on the same physical principle as their larger cousins. Micropumps with piezoelectric actuators have been fabricated. Other actuators such as thermopneumatic, electrostatic, electromagnetic or bimetallic can be used. These exceedingly minute positive-displacement pumps require even smaller valves, seals and mechanisms, a not-too-trivial micromanufacturing challenge. In addition, there are long-term problems associated with wear or clogging and consequent leaking around valves. The pumping capacity of these pumps is also limited by the small displacement and frequency involved. Gear pumps are a different kind of positive-displacement device.
U.S. Pat. No. 6,116,863 to Ahn et al. discloses a microactuated device and method of making the same in which an electromagnetic driver, overlapping a magnetically permeable diaphragm, is utilized to drive the microactuated device. The electromagnetic driver is used to provide the motive force for a microactuated device, which may be a micropump, microvalve, and the like. The electromagnetic driver is overlapped over a diaphragm.
U.S. Pat. No. 5,074,947 discloses a flip-chip bonding technique for bonding pads of a flip-chip with pads of a substrate.
The following papers are also related to the present invention:
1) xe2x80x9cA Board-Level Electro-Microfluidic Systems Fabrication Process Based on Electronic Design Methodologyxe2x80x9d by S. Martel, J. Au and I. Hunger, 1ST ANNUAL INTERNATIONAL IEEE-EMBS SPECIAL TOPIC CONFERENCE ON MICROTECHNOLOGIES IN MEDICINE and BIOLOGY, pp. 316-321, Oct. 12-14, 2000, Lyon, France;
2) xe2x80x9cFluidic Components Based on Ferrofluidsxe2x80x9d by A. Menz, W. Benecke, R. Pxc3xa9rez-Castillejos, J. A. Plaza, J. Esteve, N. Garcia, J. Higuero and T. Dxc3xadez-Caballero, 1ST ANNUAL INTERNATIONAL IEEE-EMBS SPECIAL TOPIC CONFERENCE ON MICROTECHNOLOGIES IN MEDICINE and BIOLOGY, pp. 302-306, Oct. 12-14, 2000, Lyon, France;
3) xe2x80x9cA Simple Packaging Process for Chemical Sensorsxe2x80x9d by M. E. Poplawski, R. W. Hower and R. B. Brown, SOLID-STATE SENSOR AND ACTUATOR WORKSHOP, Hilton Head, S.C., Jun. 13-16, 1994; and
4) xe2x80x9cLow-Stress 3D Packaging of a Microsystemxe2x80x9d by A. Morrissey, G. Kelly and J. Alderman, SENSORS AND ACTUATORS A 68 (1998), pp. 404-409.
An object of the present invention is to provide improved laminated devices and methods of making same.
In carrying out the above object and other objects of the present invention, a microactuated device of the sandwich type is provided. The device includes a substrate having outer insulating layers and inner insulating layers sandwiched between the outer insulating layers. An electromagnetic inductor is housed within the inner insulating layers between the outer insulating layers to produce a magnetic field. A diaphragm is coupled to one of the insulating layers so that forces exerted by the magnetic field cause movement of the diaphragm.
The substrate may be a laminate such as multilayer circuit board.
The inductor may be a solenoid.
The solenoid may include electrically conductive traces disposed on at least one of the inner insulating layers or on a plurality of the inner insulating layers.
The solenoid may also include a magnetic core surrounded by the traces.
The device may further include a fluid channel formed in at least one of the inner insulating layers, and a pump chamber formed in one of the insulating layers in fluid communication with the fluid channel. The diaphragm may be movable between first and second operative positions to vary the volume of the pump chamber.
The device may further include a plurality of electromagnetic inductors housed within the inner insulating layers between the outer insulating layers to produce corresponding magnetic fields and a plurality of diaphragms coupled to one of the insulating layers so that magnetic forces exerted by their respective magnetic fields causes movement of the diaphragms. The device may further include pump chambers formed in one of the insulating layers in fluid communication with the fluid channel wherein each of the diaphragms is movable between first and second operative positions to vary the volume of its respective pump chamber.
The device may further include a valve chamber formed in one of the insulating layers in fluid communication with the fluid channel wherein the diaphragm is movable between first and second operative positions within the valve chamber to operate as a valve.
The device may further include a channel opening formed through a first outer insulating layers and in fluid communication with the fluid channel.
The device may further include a sensor opening formed through a first outer insulating layer and in fluid communication with the fluid channel and a microsensor supported on the first outer insulating layer over the sensor opening which fluidly communicates the microsensor with the fluid channel.
The device may further include a plurality of separate fluid channels formed in at least one of the inner insulating layers.
The fluid channel may have different channel portions and a pair of the channel portions may be defined by hydrophillic material which are fluidly communicated by a channel portion defined by hydrophobic material to form a valve.
The microactuator may be completely housed within the inner insulating layers between the outer insulating layers.
The fluid channel may be shaped to form a slope-based valve therein.
Further in carrying out the above object and other objects of the present invention, a sandwich type device having a microchannel formed therein is provided. The device includes a substrate having outer insulating layers and inner insulating layers sandwiched between the outer insulating layers. A microchannel is formed in at least one of the inner insulating layers between the outer insulating layers.
The microchannel may be formed in a plurality of the inner insulating layers.
The substrate may be a laminate such as multilayer circuit board.
The device may further include one or more pump chambers formed in one of the insulating layers in fluid communication with the microchannel.
The device may further include a valve chamber formed in one of the insulating layers in fluid communication with the microchannel.
The device may further include a channel opening formed through a first outer insulating layer and in fluid communication with the microchannel.
The device may further include a sensor opening formed through a first outer insulating layer and in fluid communication with the microchannel and a microsensor supported on the first outer insulating layer over the sensor opening which fluidly communicates the microsensor with the microchannel.
The device may further include a plurality of separate microchannels formed in at least one of the inner insulating layers.
The microchannel may have different channel portions. A pair of the channel portions may be defined by hydrophillic material which are fluidly communicated by a channel portion defined by hydrophobic material to form a valve.
The microchannel may be shaped to form a slope-based valve therein.
Still further in carrying out the above object and other objects of the present invention, a method of making a sandwich-type, laminated device having a microchannel formed therein is provided. The method includes providing a plurality of insulating layers, and removing a section of at least one of the insulating layers to form at least one inner insulating layer having an elongated slot formed therein. The method also includes assembling the insulating layers to form a stack of insulating layers wherein the at least one inner insulating layer with the elongated slot is sandwiched between outer insulating layers to form the microchannel. The method further includes bonding the stack of insulating layers together to form the sandwich-type, laminated device with the microchannel therein.
The step of bonding may include the step of heating and pressing the stack of insulating layers together.
The method may further include removing a section of one of the insulating layers to form a sensor opening in one of the outer insulating layers. The step of assembling may include the step of aligning the sensor opening with the elongated slot so that the elongated slot is in fluid communication with the sensor opening.
The method may further include flip-chip mounting a microsensor over the sensor opening so that the microsensor is in fluid communication with the microchannel.
The microsensor may have at least one electrical contact and wherein the method may further include sealing the at least one electrical contact from any fluid in the microchannel.
The step of removing may form a slope-based valve in the microchannel.
The above object and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings.